A fluid level detector is used in a fuel tank of a vehicle for detecting a fuel level in the tank. The fluid level detector has a float, a float arm, a float arm holder, a main body, an electrical resistance element, and a sliding contact. The float arm supports the float floated on the fluid. The float arm holder and the main body hold the float arm and the float arm holder in a manner that the float arm is rotatable, respectively.
The electrical resistance element having an end that is electrically connected to an external circuit is fixed to the main body. The sliding contact slides on the resistance element according to rotation of the arm holder while it is pressed against the resistance element. The fluid level is detected by measuring an electrical resistance between the sliding contact and the end of the resistance element.
When the fuel surface is riffled due to vibration of the vehicle, relative movement occurs between the float and the fuel. As a result, static builds up due to friction between the float surface and the fuel. If the arm holder is made of non-conductive material such as resin as proposed in JP-A-9-5145, the static charges on the float arm. If the static is discharged between the float arm and the sliding contact, output signals from the fluid level detector are distorted. As a result, accuracy of the fluid level detector decreases.